Electric welding apparatus



N. E. ANDERSON ELECTRIC WELDING APPARATS 2 Sheets-Sheet 1 INVENTORNELSON E. ANDERSON BW i ATTORNEY Nov. 17, 1953 Filed Feb. 5, 1951 Nov.17, 1953 N. E. ANDERSON ELECTRIC WELDING APPARATUS 2 Sheets-Sheet 2Filed Feb. 5, 1951 INVENTOR NELSON E. ANDERSON BY/// m ATTORNEY PatentedNov. 17, *19531 ELECTRIC WELDING APPARATUS Nelson E. Anderson, BerkeleyHeights, N. J., assigner to Air Reduction Company, Incorporated, New`Kork, N. Y., a corporation of New York Application February 5, 1951,Serial No. 209,430

6 Claims.

This invention relates to gas shielded metal arc welding Patent Number2,504,863, issued .April 18, istil, to Albert Muller et al. and assignedto the saine assignee as the present application, discloses a gasshielded metal arc Welding method in which a bare consuming wireelectroce is fed to a Welding arc within an enve lope of shielding gas.ln the preferred form ci that invention the shielding gas is a monatomicinert gas. The electrode wire and Work are uSu- :i

ally of substantially identical composition and be any tveldable metalor alloy, ferrous or non-ferrous. In the practice ci this invention, thewelding currents employed be relatively high, being of the order oi 290to 350 aniperes on Wires of Tg inch diameter. The Wire is fed to the areat the Wire burn ofi rate to maintain equilibrium in the arc, Which feedrate may be of the order of 150 to 309 inches per minute. Thisrelatively high Wire feed rate, coupled with the requirement forintroducing high value welding currents into the rapidly moving wire,presents wire feeding and current Contact problems.

It has been found, for instance, that in many applications of this gasshielded, bare Wire metal arc Welding process, the wire electrode mustbe physically and chemically clean in order to obtain sound welddeposits. This is disclosed in a co-pending application by AlbertMuller, Serial No. 159,051, filed April 29, 1950, and assigned to thesame assignee as the present application. This makes it impossible touse lubricants of any kind on the Wire, which increases the difficultywith which the wire may be fed through the apparatus. This dimculty ismultiplied Where the wire is pushed through a substantial length offlexible casing to a portable Welding gun for manual Welding operations,inasmuch as such operations produce a constantly changing amount ofbending of the casing with consequent variations in resistance tofeeding. It is further multiplied Where the wire is aluminum or asimilar soft metal which, when clean, will cold Weld or gall in theapparatus as it is being ied, thereby -jamming the device. The term gallas used herein, refers to that phenomenon in which surface metal of onemember is actually bonded to a second member with which it is in contactby a cold formed molecular bond of suicient tenacity to remove surfacemetal from the first member as the rst member passes in intimate contactwith the second member.

It has also been found necessary to control the point at which theWelding current is introduced into the Wire Within the apparatus. Thereare two important reasons for this. One reason is that substantial heatis developed at the point where the current is transferred to theelectrode Wire because of contact resistance. For purposes of safety andlong trouble-free apparatus life, it is essential that this effect beminimized and localized. A second equally or more important reason isthat the length of electrode Wire carrying the Welding current is veryimportant to the Welding process and the results it produces. It isextremely important that this length (from point of current introductioninto the wire to the arcing end) be kept (1) constant and (2) short. Thereason for this is that When the current density in the electrode isrelatively high there is a large amount of resistance heating ci theportion of the Wire through which the welding current iiows. This iseffectively a high intensity preheat of the wire which affects theelectrode burn-off rate and the welding energy distribution. ln order toobtain consistent and uniform Welcls, this resistance heating must bemaintained constant. For best results this resistance heating must alsobe as small as possible. This is accom-` plished by introducing thecurrent to the Wire as near the arc as practical and by preventingcurrent introduction to the wire at any but the preselected location.

1t is, therefore, an object of this invention to provide gas shieldedconsumable electrode arc Welding apparatus through which clean bareelectrode Wire may be fed without excessive friction and Withoutgalling.

Another object is to provide gas shielded consumable electrode arcWelding apparatus Within which the Welding current is introduced intothe electrode Wire only at a preselected location within the apparatus.

Another object is to provide a flexible casing through which chemicallyclean bare wire may be continuously fed Without causing chatter withinthe casing, and in which no galling of the wire will occur. These andother objects, which will become apparent from the following speciiication, are achieved by providing apparatus hav ing certain novel liningelements arranged and supported in a novel manner as exemplied by theaccompanying drawings.

Figure 1 is a longitudinal sectional View through a manual welding gunforming a portion of the present invention.

Figure 2 is a transverse section of the gun taken at 2 2 of Figure 1.

Figure 3 is a longitudinal sectional View partially broken away of thecasing assembly connecting the gun of lligure i with the w' feed rollunit and the shielding supply.

Figure l is a sectional perspective view of the casing gun-end iitting,illustrating more clearly the details oi its construction, and themanner in which gas iovvs through the fitting.

The gun proper (Figure 1) consists of an outer barrel i, a handle and ahandle cover 3, all of thermal and electrical insulating material, a gasnozzle i and gas adapter an inner barrel assembly il, a barrel assemblyinsulating Yliner l, an annular head type of stud i3, an assembly nut S,an insulating bushing it, a stud nut l i, a trigger switch iii, operatedby a trigger a jog switch i5, operated pushbutton i3d, and a Contacttube ifi.

Welding current, carried tothe gun by an insulated Welding cable whichis soldered into lug- It, is transferred to the stud and lug il throughthe stud nut l i which rides against the tongue oi' lug Une iace of studil, rests against a shoulder oi' the inner barrel assembly E which isformed pinion ill having an axial hole therein so it can be iitted overand soldered to an inner barrel member lll. Nut is threaded on the endof he inner barrel, member of inner panel assembly il, so that thelatter is held securely in place. Stud ii, stud nut ii, inner barrel it,pinion and nut o are ail made oi materials that are good electrical andthermal conductors, such as copper and brass. A sleeve 2U is soldered tothe i'orvvard end or" inner barre it. This sleeve serves as a gas lovvcontrol element and simultaneously maintains the inner barrel assemblyconcenti'ically located Within the outer barrel. It is made out of steelpinion 'wire and has a through hole ior the Wire, a counterbore to seatinsulating liner a larger counter bore to seat inner barrel le and atapped hole to receive Contact tube Hl, all holes being concen" tric.The spaces between the teeth of the pinion Wire form a series oflongitudinally directed and concentrically arranged gas ports whichassist in the formation oi the proper gas iloW pattern for adequate gasshielding of the Weld. Aiter the inner barrel assembly has beensoldered, sleeve 2e is preferably silver plated to increase theelectrical and thermal contact conductivity and prevent corrosion.'liihile inner barrel assembly t and insulating liner 'i' are applicableor all sizes oi Wire within the operating capacity of the gun, contacttube it must be changed for dii'erent sizes of Wire. The hole in contacttube I4 is usually only a few thousandths oi an inch larger than thediameter of the Wire electrode 2i to assure adequate electrical contactbetween the contact tube and the Wire. The current is transferred tocontact tube itl through the threads in sleeve The internal diameter oi'the contact tube should not exceed the wire diameter plus 20% and thisinternal diameter should be maintained for a length oi' at least 25times the internal diameter for best operation.

insulating barrel l is tapped at both ends. Pit the rear end it receivesa casing assembly gun-end end fitting lil and at the forward end itreceives the gas nozzle adapter Gas nozzle il is prei erably made withradiating fins, such as the three concentric ns 2li, 2o, and 23, whichincrease in diameter in a direction away from the Welding area. Thenozzle 4 and the fins Ell, i5 and 2t, are made of good heat conductorssuch as copper. The concentric ns give a large surface area to radiatethe heat and prevent overheating of the nozzle. Gas nozzle adapter 5.into which gas i gather a lo-assembly. lThe end iaoe :lit

'4 nozzle assembly 4 screws, is made of a very poor heat conductor, suchas stainless steel, and is inachined to have a very thin section toincrease its resistance to heat transfer in order to protect t i end ofouter barrel l from extreme high teni tures. Nozzle il and adapter andthe outer barrel i preferably cooperate to forni an unob structed gasflow passage free of severe changerin cross sectional area and i'ree ofsevere on of gas flow direction for an axial distance oi at least fivetimes the nozzle orifice diameter.

yEhe c sing (Figure 3) is a completely insulate.)A asseznbi in which theWire is conveyed drive roll assembly 2l' to the gun. nrt Wire has beenpulled, by power driven rolls trom a reel or other source of supply (notshown it enters connector insert 3d which is inade of nylon. Insert tillis threaded into and on a shoulder in connector insert nut and w.

n protrudes therefrom into gas connection assoltibly 32. Connectorinsert nut 3l has an external hexagonal shoulder which rests against ones oi' an adjustment block "m The end oi in). insert nut 3i, whichprotrudes from tno othel side oi' block 33, is threaded and screws intoLe.. connection assembly 32 thus locking c connector insert nut supplyfitting in place with f' ustment bloot: L13. The downstream end siconnec soldering assembly or;

ernal ead to which the ne: portion of the casing is connected y unionnu: The flexible portion of the casing nu cuties a fioziible hollowmetal casing sold/:rou into a feed-roll-end fitting 3G and a gun-endfitting 3l. The feed-roll-end tting is couilterbored to receive a nylonliner ssernbly, of slsting of a nylon liner 36 and a nylon plug sil.

Liner and plug Sil are permanently bonded t butts against the end aceor' the nection assembly 32 when nut 3d is tightened o the flanged endof end fitting 36. End fitting has a series of concentrically arrangedlongitudinal holes 36 drilled through it to pass shielding as will bemore iully disclosed inater. Nyon liner 3d extends end ntting 3l andinto bushing ld, the counterbore of end nt'ting 3?. is insulated fromits carrier tubes until contact tube i4. Nylon liner 3s does n againstinsulating liner 7. The nylon lin made a free nt in bushing i9. Free end'play j. al" to accommodate the dimensional bility of the nylon linerand to increase the iA c y ol the casing. Motion oi the t duces tensionin the nylon liner cans g i elongate in a downstream direction and wereit not for the fact that it is supporte-l only at tl upstrean'i end,with room o ovfnstr H pansion, the liner would buckle obstruct freefeeding of Wire through it, resulting in chaiv tering and/or jamming.Different oi" may require different connector inserts til, nyir i linersnylon plugs iloxible cash-lgs end ittings feed-roll-end fittings obushings il. Where the Wire passes from che piece to the next, the holein the new piece either be greater in diameter than the iirst or have anentering taper to keep the wire hanging up.

Shielding gas is introduced into the casing um mediately downstream ofthe drive roll bly 'through the gas supply tting 2i) and into the gunthrough end tting 3l.

ot butt Gas connectlon assembly 32 consists of gland 4B, con' ectorbarrel 4I, tube 42 and gas fitting d3. The connector barrel 4| is tappedat the rear end to receive connector insert nut 3|. It is counterboredfrom the other end to receive tube 42, which is soldered in place. Alarger diameter ccunterbore forms an annular space 2 around the tube.There is a transverse hole half way through barrel lli for the gasiitting llt. A series of small holes 43 is drilled in gas connectorbarrel il joining the annular space i' and the hole for the gas fitting.The gas fitting 43 has a radius cut on it so that gas may flew throughthe gland 40 (which is soldered into the gas fltting s3) through gasfitting 43, and then through the series of holes 43 into the annularspace 42 cf gas connector barrel 4l. The feed-roll-end fitting 3e liesalong the same axis as the gas connector assembly 32. The series ofholes 5&3 drilled in the feed-roll-end fitting 36 are drilled on thesame radius as the holes d3 and allow the gas to flow into the space 46between the casing and a hose it. The hose 45 is clamped to the endfittings 36 and 3l. The gun-end fitting 3l has circumferential V grooves3l to provide a positive gripping surface for seating and clamping thehose. The gun-end fitting has longitudinal slots 48 that break throughto the centrai hole to provide gas passages. The manner which the gaspasses through this portion of the apparatus is best seen in Figure 4.This end fitting 3l' screws into outer barrel l. Grooves in nut andclearance around stud 8 permit the gas to pass through the barrel. Gaspasses to the welding area through the spaces between the teeth of studI8 and sleeve 20.

Control wires for trigger switch l2 and jog switch i3 are brought in bythree-conductor cable 44.

Thus it may be seen that a continuous bare wire metal arc welding toolhas been devised that overcomes the problems of wire feeding and currenttransfer. The wire is fed through this device all the way from the powerdriven feed rolls to the contact tube within a non-galling low-frictioninsulating structure, free of metal to metal contact. For all portablewelding apparatus of this type, and especially for manual apparatus asfully disclosed herein, the casing must be light and flexible. The wiremust be able to feed through it equally well whether the casing be drawntaut or hanging or lying in loops or fair curves. This makes the choiceof casing liner material critical. 1t must present a relatively lowcoefficient of friction when used without a lubricant, it must beflexible, it must be electrically non-conducting, it must resist wearand abrasion, and it must be of such a nature as not to cause gallingwith chemically clean wire, particularly with wires of metals likealuminum or magnesium. One such suitable liner material is nylon, a nowwell-known synthetic polymer. Folyhexamethylene adipamide, which isknown commercially as FM 10,001 nylon, is a particularly gcod linermaterial having all the required properties. The selection of nylon as alining material represents a distinct advance in apparatus of this type.A still further advance, however, is affected by supporting this linerin tension. This mode of support eliminates the tendency of the liner tobuckle and chatter within the casing.

The rigid non-metallic insulating members through which the wire is fedmay be made of nylon, as above, but may also be made of other theapparatus.

fill

d tough, low-friction plastics, such as a fibre glass reinforcedtnermosetting melamine resin. lnsulating liner l in the gun is such amember.

In addition to reducing the mechanical resistance to feeding to aminimum, the entire passage of the wire through these insulatingmaterials eliminates the possibility of electrical contact, andtherefore the transfer of current to the Wire anywhere but at thedesired location; nainely within the contact tube I4. This preventspitting of the wire and gun and casing elements due to arcing therein.Such pitting, if present, greatly impedes the free feeding of the wirethrough This insulating feature also controls and minimizes resistanceheating within the welding wire.

The copper gas nozzle 23 and the stainless steel adapter 5 areelectrically floating inasmuch as they are screwed into the insulatingouter barrel l. This eliminates any possibility of arcing to the nozzleor adapter from the Wire or contact tube or from the nozzle or adapterto the work when the gun is laid down on, or brushed against, the work.The gun is fully insulated for the operators safety.

'While the preferred embodiment of the invention has been disclosedherein, it is understood that certain modifications may be made withoutdeparting from the spirit of the invention as defined by the followingclaims.

I claim:

1. A flexible casing for the continuous passage therethrough ofchemically clean bare wire comprising a flexible metal conduit and aliner of flexible non-galling tubing, said liner of flexible tubingbeing longitudinally supported Within said flexible metal conduit onlyat the end through which said wire enters to form an assembly in which afree space is provided at the unsupported wire discharge end of saidliner to accommodate the dimensional instability of said liner as it isplaced in tension by the frictional forces exerted on said liner by saidwire passing therethrough.

2. A exible casing for the continuous passage therethrough of chemicallyclean bare wire comprising a flexible metal conduit and a liner oflexible nylon tubing, said liner of flexible nylon tubing beinglongitudinally .supported within said flexible metal conduit only at theend through which said wire enters, to form an assembly in which a freespace is provided at the wire discharge end of said liner to accommodatethe dimensional instability of said nylon liner as it is placed intension by the frictional forces exerted on said liner by said wirepassing therethrough.

l3. Welding apparatus comprising power driven wire feed rolls, aflexible casing into which wire is delivered by said feed rolls, and awelding gun into which wireis delivered by said casing, said casingcomprising a iiexible metal conduit, a flexible nylon liner within saidconduit, means acting at the feed roll end of said casing forlongitudinally supporting said liner within said conduit while the gunend of said liner remains longitudinally unsupported to place said linerin tension by the frictional forces exerted on said liner by the passageof wire therethrough, and lowfriction electrically non-conducting liningmeans within said gun to isolate said electrode wire from all otherconducting members except a current contact member located at apreselected point within the gun.

4. In inert gas shielded depositing electrode metal arc weldingapparatus comprising a welding gun containing an inner wire guideassembly,

a welding current contact member, a surrounding outer gas-conducting andshield-forming assembly, means for supplying shielding gas to saidgas-conducting and shield-forming assembly, a nexi'ole casing connectedto the rear end of said gun and adapted to conduct Welding wire to saidgun, and power driven wire feed means for continuously supplying weldingWire to said casing, the improvement which comprises providing theflexible casing and welding gun wire guide portion with non-galling andelectrically non-conducting liners, said flexible casing liner beingnylon and beiner longitudinally supported at the wire entrance end ofsaid casing only, and having a free space provided at the gun end ofsaid liner for its unrestrained longitudinal expansion and contraction.

5. In inert gas shielded depositing electrode metal arc weldingapparatus comprising a Welding gun containinr,` an inner wire guideassembly, a. welding current contact member, a surrounding outergaswonducting and shield-forming assembly, means for supplying shieldinggas to said gas-conducting and shield-forming assembly, a exible casingconnected to the rear end of said gun and adapted to conduct Weldingwire to said gun, and power driven wire feed means for con,

tinuously supplying welding Wire to said casing, the improvement whichcomprises providing the ilexible casing and welding gun wire guide Dortion with non-galling and electrically non-conducting liners, saidflexible non-galling and elec" trically non-conducting casing linerbeing longitudinally supported at the Wire entrance end only, and havinga free space provided at the gun end of said liner for its unrestrainedlongitudinal expansion and contraction.

6. Gas shielded are Welding apparatus for use with long lengths ofchemically clean 'dexible aluminum electrode wire comprising, a manualgun containing an inner Wire guide assembly having a surface in contactwith said Wire of non-galiing electrically ncneconducting material, awelding,r current Contact member nearer the Welding are than said Wireguide assembly, a surrounding outer gas conducting and shield formingassembly, a ilexible casing assembly ci' fixed length connected to therear end or" gun to convey aluminum Welding Wire 'to said gun, saidcasirrdr having an internal surface of nylon in contact with said Wire,and power driven wire i means at the end of the flexible casingremotefiom said gun for continuously and uniformly pushing said aluminumelectrode Wire thrcugh said easing, said wire guide said contact elementto the Welding arc.

NELSON E. A\TDERSON.

References Cited in the rile of this patent UNITED STATES PATENTS NumberN Date 2,246,086 Austin i June 17, 1941 2,504,868 Muller et al Apr. 18,1950

